[tools/perf] Disable yahoo answers on N5X

They were disabled by mistake on the wrong platform.

TBR=nednguyen@google.com
NOTRY=true

Bug: 874935
Change-Id: I9b50b481e97b9f2c01cde4cc43f1627ea4663c51
Reviewed-on: https://chromium-review.googlesource.com/1181135Reviewed-by: Juan Antonio Navarro Pérez <perezju@chromium.org>
Commit-Queue: Juan Antonio Navarro Pérez <perezju@chromium.org>
Cr-Commit-Position: refs/heads/master@{#584436}

tools/perf/expectations.config

@@ -167,8 +167,8 @@ crbug.com/338838 [ All ] rendering.mobile/basic_stream [ Skip ]
 crbug.com/338838 [ All ] rendering.mobile/basic_stream [ Skip ]
 crbug.com/873013 [ Android_Webview ] rendering.mobile/yahoo_answers_mobile_2018 [ Skip ]
 crbug.com/873014 [ Android_Webview ] rendering.mobile/yahoo_answers_mobile_sync_scroll_2018 [ Skip ]
-crbug.com/874935 [ Android_Webview ] rendering.mobile/yahoo_answers_mobile_2018 [ Skip ]
-crbug.com/874935 [ Android_Webview ] rendering.mobile/yahoo_answers_mobile_sync_scroll_2018 [ Skip ]
+crbug.com/874935 [ Nexus_5X ] rendering.mobile/yahoo_answers_mobile_2018 [ Skip ]
+crbug.com/874935 [ Nexus_5X ] rendering.mobile/yahoo_answers_mobile_sync_scroll_2018 [ Skip ]
 crbug.com/865400 [ Pixel_2 ] rendering.mobile/yahoo_answers_mobile_2018 [ Skip ]
 crbug.com/865400 [ Pixel_2 ] rendering.mobile/yahoo_answers_mobile_sync_scroll_2018 [ Skip ]